Packet-based digital display interface signal mapping to bi-directional serial interface signals

ABSTRACT

A passive cable adaptor for connecting a data source device with a display device is described. The adaptor has a packet-based interface connector at one end, the connector having a positive main link pin, a negative main link pin, a positive auxiliary channel pin, and a negative auxiliary channel pin. Also at the same end is a serial interface connector, such as a serial interface connector. At the other end is an upgraded serial interface connector (e.g., enhanced serial interface) connector having high-speed transmission pins, high-speed receiving pins, and a ground pin, wherein multimedia content is transmitted over the cable adaptor and electrical power is supplied over the cable adaptor simultaneously.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 U.S.C. §119(e) to ProvisionalPatent Application No. 61/300,929, filed Feb. 3, 2010 (Attorney DocketNo. GENSP240P) entitled “Signal Mapping Between Display Port and USB3.0Compliant Devices”, Provisional Patent Application No. 61/318,727, filedMar. 29, 2010 (Attorney Docket No. GENSP241P), titled “DP Signal MappingOnto a USB Connector”, Provisional Patent Application No. 61/325,734,filed Apr. 19, 2010, titled “DP Signal Mapping Onto MicroUSB2.0Connector” (Attorney Docket No. GENSP241P2), and to Provisional PatentApplication No. 61/365,195, filed Jul. 16, 2010, titled “Display PortAux Ch Handshake for Negotiating a Higher Power Supply Voltage”(Attorney Docket No. GENSP241P3), each of which is incorporated byreference herein in their entireties.

TECHNICAL FIELD

The present invention relates generally to communication of varioustypes of data in a multimedia network. More specifically, it relates tocommunicating data directly between a multimedia device and an externaldisplay device.

BACKGROUND OF THE INVENTION

Many multimedia devices are becoming increasing popular. Such devicesare being used more frequently as devices for taking and storing videos,picture, music files and software applications (“apps”) and the like,for a wide variety of functions, and so on. Currently, these deviceshave various ports for data transfer. They are used for powering thedevice or backing up data. They are also used for transmitting data ontoand from phones.

Some of these ports support standards which currently have onedifferential pair, D+ (Diff_pos) and D− (Diff_neg). This is half-duplexwhich means that data is sent and then the device must wait for a replybefore sending data again (essentially, a send, wait, get reply, send,wait, get reply pattern . . . ). Upgraded versions of these standardsmay be significantly faster and are full duplex. They may support a Txand Rx pair which allows data to be sent without first having to waitfor a reply. This enables extremely quick downloads of digital video,such as movies and other high-volume data, and makes the devices evenmore multimedia-centric. For example, multimedia device manufacturersare beginning to incorporate these standards into their phones, and itis expected that users will want to be able to download or showpictures, videos, and other content directly on an external displaydevice, such as a TV or a computer monitor from their phones or otherdevices (without use of a computer or other component). Thus, it wouldbe desirable to be able to map digital multimedia content onto thesestandards from a packet-based digital display interface.

SUMMARY OF THE INVENTION

In one aspect of the invention, a method of transmitting data andsupplying power between a multimedia data source device and an externaldisplay device is described. High-speed transmission signals of adifferential, bi-directional, serial interface (hereafter “serialinterface”) are mapped to main link signals of a packet-based interface.High-speed receiving signals are mapped to auxiliary channel signals ofthe packet-based interface. These mappings enable transport of amultimedia data stream from the source to the external display device.Power is also supplied from the external display device to the sourcedevice using a serial interface connection while simultaneouslytransporting the multimedia data stream.

In one embodiment, a ground signal of the data source device is mappedto a packet-based display interface HPD signal. In another embodiment,high-speed transmission (hereafter “HSTX”) positive signal of the serialinterface is mapped to a main link positive signal and an HSTX negativesignal is mapped to a main link negative signal. In another embodiment,HSTX positive signals are mapped to an auxiliary channel positive signaland high-speed receiving (hereafter “HSRX”) negative signals of theserial interface are mapped to auxiliary channel negative signals. Inanother embodiment, an HSRX negative signal is mapped to a packet-basedinterface negative auxiliary pin signal. In another embodiment, power issupplied through a packet-based interface power pin if the externaldisplay device does not have serial interface downstream capability. Inanother embodiment, power is supplied through a Vbus pin and apacket-based interface power pin, if the external display device doeshave serial interface downstream capability.

In another aspect of the invention, a passive cable adaptor forconnecting a data source device with a display device is described. Theadaptor has a packet-based interface connector at one end, the connectorhaving a positive main link pin, a negative main link pin, a positiveauxiliary channel pin, and a negative auxiliary channel pin. Also at thesame end is a serial interface connector. At the other end is anupgraded or enhanced serial interface connector having HSTX pins, HSRXpins, and a ground pin, wherein multimedia content is transmitted overthe cable adaptor and electrical power is supplied over the cableadaptor simultaneously.

General aspects of the invention include, but are not limited tomethods, systems, apparatus, and computer-readable media for enablingmessage transmission in multimedia device networks.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention and the advantages thereof may best be understood byreference to the following description taken in conjunction with theaccompanying drawings in which:

FIG. 1 is a simplified network diagram showing a multimedia deviceconnected to an external display device via a cable in accordance withone embodiment;

FIG. 2 is a block diagram of a serial interface receiver connectorcomponent of a multimedia device;

FIG. 3A is a pin diagram of a packet-based display interface receiverconnector of an external display in accordance with one embodiment;

FIG. 3B is a block diagram of a serial interface receiving connector onan external display;

FIG. 4 is a pin diagram of a packet-based display interface receiverconnector of an external display in accordance with an alternativeembodiment;

FIG. 5 is a detailed block diagram showing in greater detail thecomponents of FIG. 1 in accordance with one embodiment;

FIG. 6 is a block diagram of packet-based interface source plugconnector in accordance with an alternative embodiment;

FIG. 7 is a flow diagram of a process of transmitting data and providingpower between an external display device and a multimedia device inaccordance with one embodiment;

FIG. 8 is a flow diagram of a process of supplying power from theexternal display to the multimedia device in accordance with oneembodiment;

FIG. 9 is an overview block diagram showing a connection between amultimedia device and an external display device in accordance with oneembodiment;

FIG. 10 is a block diagram showing in greater detail the componentsshown in FIG. 9 in accordance with one embodiment; and

FIG. 11 is a block diagram of a device PCB having a passivebi-directional switch (multiplexer) in accordance with one embodiment;and

FIG. 12 is a block diagram of a device PCB where a packet-based ML TXPHY and a USB PHY share the same pads in accordance with an alternativeembodiment.

In the drawings, like reference numerals are sometimes used to designatelike structural elements. It should also be appreciated that thedepictions in the figures are diagrammatic and not to scale.

DETAILED DESCRIPTION

Reference is made to particular embodiments of the invention. Oneexample of which is illustrated in the accompanying drawings. While theinvention will be described in conjunction with the particularembodiment, it will be understood that it is not intended to limit theinvention to the described embodiment. To the contrary, it is intendedto cover alternatives, modifications, and equivalents as may be includedwithin the spirit and scope of the invention as defined by the appendedclaims.

Aspects of the invention pertain to methods and apparatus for enablingtransmission of data from a source to sink and simultaneously enablingthe supply of power from the sink to the source. The source supports apacket-based interface and an enhanced serial interface. The sinksupports the same packet-based interface and is a serial interface hostand is able to supply power to the source, as described in greaterdetail below. The invention is an apparatus, referred to as a passivecable adaptor that has an enhanced serial interface plug connection atone end that connects to a device, such as a multimedia device, and atthe other end has two connectors: a packet-based interface plugconnection and a serial interface plug connection, both of which connectto the external display device.

In one embodiment, methods for mapping a 1-lane main link packet-baseddisplay signal onto a enhanced serial interface connector for enablingconnectivity from a packet-based source packet-based displayinterface/enhanced serial interface equipped handheld device to anexternal packet-based display interface-enabled and serial interfacedisplay device are described. The methods allow for the simultaneousoperations of a packet-based source interface isochronous transport ofmultimedia audio-visual (AV) streams and serial interface operationwhile the mobile phone is powered by the external display device. The AVstream may be have High-bandwidth Digital Content Protection (HDCP)content protection

FIG. 1 is a simplified network diagram showing a multimedia deviceconnected to an external display, such as a TV, via a passive cableadaptor. The various embodiments described herein related to methods andcomponents in the passive cable adaptor. A multimedia device 102 is amultimedia-centric computing device capable of performing numerousfunctions in addition to being a mobile phone. In other embodiments, itmay be an IP-enabled computing device, such as a tablet or a mobilegaming device. In other embodiments, it may not be IP-enabled and maysimply be a multimedia handheld device used primarily for takingpictures and video, storing and watching movies and other audio-visualcontent, storing and reading electronic versions of books andperiodicals (e-books), storing and listening to music, and so on.Multimedia device 102 is a packet-based interface source (hereafter“packet-based source”) and an enhanced serial interface capable device.Component 110 in multimedia device 102 is a standard enhanced serialinterface receiving connector, the type of connector many mobile phoneand handheld device manufactures are or will be providing on theirdevices due to its significant advantage over the previous generationserial interface. This connector or component 110 is commonly referredto as simply as a serial interface port. As noted, in one embodiment,multimedia device 102 is a source device for multimedia content thattransmits data to a sink device, where the content is played ordisplayed.

In one embodiment, the sink device is an external display device 104,such as a TV or a computer monitor. In the described embodiment,external device 104 is a standard serial interface host. It may also bean enhanced serial interface host, which would make it capable of beinga host for 2.0 (since 3.0 is a superset of 2.0). Display device 104 hastwo connectors relevant to various embodiments of the present invention.One is a packet-based display interface source receiver connector 116.The other is a serial interface receiver connector 118. These connectorsare described in greater detail below.

The external display device 104 and multimedia device 102 are connectedby a passive cable adaptor 106. At one end of cable 106 is an enhancedserial interface plug connector 108 which is capable of coupling toreceiver connector 110 of multimedia device 102. At the other end aretwo plugs: a packet-based interface source plug connector 112 and aserial interface plug connector 114. Plug connector 112 is capable ofcoupling with the interface source's receiving connector 116 and plugconnector 114 can couple with serial interface receiver connector 118.Multimedia content is transmitted from multimedia device 102 to displaydevice 104 where it is displayed and, simultaneously, power is providedfrom display device 104, for example a TV, to multimedia device 102. Theamount of power supplied depends on the configuration and use of pins inreceiver connectors 116 and 118 in display device 104 and in connector110 in multimedia device 102. These configurations are described indetail below. Generally, in the described embodiment, the amount ofpower provided may range from 3.3V/500 mA to a total of 8.3V/500 mA.

FIG. 2 is a block diagram showing pin connector designations of enhancedserial interface receiver connector 110 of multimedia device 102.Enhanced serial interface has a serial interface backward compatibleportion. This portion includes the half-duplex, bi-directional pins, D+202 and D− 204. This differential pair is capable of transmitting dataat 480 Mbps. Also part of this backward compatible portion is a Vbus pin206 and a GND (ground) pin 208. The role of these pins is described inthe figures below.

The enhanced serial interface extension portion is composed of theremaining five pins. There is a high-speed TX+ pin 210 (“HSTX”) andhigh-speed TX− pin 212 pair for transmitting data from a host or sourcedevice, such as multimedia device 102 to a sink or hub device, such asexternal monitor 104. HSTX+ 210 and HSTX− 212 are AC-coupled and cantransmit data at 5 Gbps. A high-speed RX+ pin 214 and a high-speed RX−pin 216 (“HSRX”) comprise a pair for receiving data from a hub/sinkdevice (e.g., TV 104) at the host (e.g., multimedia device 102) and isalso AC-coupled and can transmit data at 5 Gbps. This pair (HSRX+ 214and HSRX− 216) and the pair HSTX+ pin 210 and HSTX− pin 212 comprise afull-duplex, bi-directional coupling between multimedia device 102 andexternal device 104. That is, data can be transmitted in both directionsat the same time, unlike in the serial interface protocol, providing fora speed that is faster than the increase in actual transmission speed(458 Mbps vs. 5 Gbps). There is also a GND pin 218 that is part of theenhanced serial interface extension portion.

Moving now to packet-based display interface source receiving connector116 of external display 104, there are five pins as shown in FIG. 3A. Amain link lane0+ (ML0+) pin 302 and a main link lane0− (ML0−) pin 304are used for transmitting data from a source to a sink at 5.5, 2.7, or1.62 Gbps and are AC-coupled. ML0+/− pins are specific to a packet-baseddigital interface described below. There is also an auxiliary channelpair which functions as a bi-directional sideband channel in thepacket-based digital interface protocol. An AUX CH+ pin 306 and AUX CH−pin 308 pair enables 1 Mbps transmission and are half-duplex andbi-directional. There is also a pin 310 for hot plug detect (HPD) fromexternal display device 104 (sink) to multimedia device 102 (source). Inthis embodiment, there is no connection for DP_PWR (part of thepacket-based display interface). In one embodiment, the power sourcefrom sink to source is 3.3V/500 mA. The interface referred to herein isa packet-based, serial digital display interface that is open andscalable and supports plug and play. Unlike conventional displayinterfaces that transmit a single video raster plus timing signals(e.g., Vsync, Hsync, DE, etc.), the packet-based interface referred toherein provides multi-stream packet transfer capable of transferring oneor more packet streams simultaneously in the form of virtual pipes orlanes established within a physical link or main link. A number of datastreams are received (from a source device) at a transmitter (acomponent of the physical link) that, if necessary, packetizes each intoa corresponding number of data packets. The data packets are then formedinto corresponding data streams, each of which are passed by way of anassociated data lane to a receiver (also a component of the physicallink).

The link rate (i.e., the data packet transfer rate) for each virtuallink or lane can be optimized for the particular data stream resultingin the physical link carrying data streams, each having an associatedlink rate (each of which may be different depending on the particulardata stream). Thus, the link rate is independent of the native streamrates. In this way, the packet-based interface provides a scalablemedium for the transport of video, graphics, audio, and applicationdata. The interface also supports hot-plug detection (HPD) andautomatically sets the physical link (or pipe) to it optimumtransmission rate. The interface provides for low pin count and purelydigital display interconnect for all displays, including HDTV. Thepacket-based nature of the interface provides scalability to supportmultiple, digital data streams such as multiple video/graphics streamsand audio streams for multimedia applications. In addition, a USBtransport for peripheral attachment and display control can be providedwithout the need for additional cabling.

One feature of the packet-based, display interface is that it has anauxiliary channel logical sub layer. The major functions of theauxiliary channel include data encoding and decoding, framing/de-framingof data and two options for auxiliary channel protocol. One is astandalone protocol (limited to link setup/management functions in apoint-to-point topology) which is a lightweight protocol that can bemanaged by the Link Layer state-machine or firmware. The other is anextended protocol that supports other data types such as USB traffic andtopologies such as daisy-chained sink devices. In the describedembodiment, the packet-based interface signal is transmitted over asingle lane on the main link. In other embodiments, two or four lanesmay be used over the main link. In this case, the auxiliary channel canbe disabled and can then be mapped to D+ and D−, which can then providetwo main link lanes. Further details on the packet-based displayinterface are described in patent application Ser. No. 11/742,222,titled “Integrated Packet-Based Video Display Interface and Methods andUse Thereof,” filed on Apr. 30, 2007 (Attorney Docket No. GENSP013C3).Packet-based interface configuration data fields that are relevant tovoltage shifts are shown in Table 1 below.

Returning now to the figures, FIG. 3B shows a serial interface receivingconnector 118 on an external display 104. These pins correspond to theserial interface backward compatible portion of connector 110 in FIG. 2.There is a differential pair composed of a D+ pin 312 and a D− pin 314that enable 480 Mbps transmission and are half-duplex andbi-directional. There is also a Vbus pin 316 for power (5V/500 mA forserial interface) and a GND pin 318.

In another embodiment, connector 116 of external display device 104 mayhave a different configuration when multimedia device 102 gets powerfrom device 104 and when device 104 does not have a downstream USB port(i.e., no serial interface connection from external display device 104to multimedia device 102). In this embodiment, phone 102 receives powerfrom DP_PWR pin as well as from Vbus pin 316.

A configuration of connection 116 is shown in FIG. 4. Here the ML0+ pin402 and ML0− pin 404 are the same as in FIG. 3A. The AUX CH+ pin 406 isalso the same. Pin 409 is used for HPD. Pin 410 is used solely forDP_PWR and is not shared with HPD. This is also the case with FIG. 3A,describing the first embodiment, where external display 104 has a USBdownstream port with Vbus power. Recall that in the first embodiment,power is provided to multimedia device 102 via Vbus pin 316 on serialinterface, that is, the backward-compatible connection portion. Whenexternal display device 104 is only a serial interface host (not aenhanced serial interface host), the power is limited to 5V/500 mA. Incable adaptor 106, AUX− (pin 408) and HPD (pin 409) are connected ormutexed, shown in more detail in FIG. 6 below.

FIG. 5 is a detailed block diagram showing in greater detail thecomponents of FIG. 1 in accordance with one embodiment. The three basiccomponents are multimedia device 102 shown as box 502, external displaydevice 104 shown as box 504, and passive adaptor cable 106 shown as area506. Connected to box 504 is enhanced serial interface receiverconnector 110 shown as box 508. Packet-based interface source receiverconnector 116 and serial interface receiver connector 118 are part ofexternal display device 104.

Adaptor cable 106 is the data communication and simultaneouspower-supplying device between multimedia device 102 and display device104. As noted above, it has an enhanced serial interface plug connector108 on one end that connects to receiver connector 110 on multimediadevice 102. On the other end are packet-based interface source plugconnector 112 that plugs into receiver connector 116 and serialinterface plug connector 114 that plugs into receiver connector 118.

The pins in all the receiver connectors and plug connectors aredescribed in FIGS. 2, 3, and 4 and are shown in more detail in FIG. 5(like number reference numbers are used for ease of explanation). Plugconnector 108 has pins 202 to 218 as described in FIG. 2A. Interfacesource plug connector 112 has pins 302 to 310. Serial interface plugconnector 114 has pins 312 to 318 as shown in FIG. 2B.

Multimedia device 102 has numerous components relevant to embodiments ofthe present invention. Starting with HSTX+ pin 210, a connection or line514 leads to Main Link (ML) TX/enhanced serial interface HSTX component(as described above, ML pertains to the packet-based interface). Pin 210maps to pin 302 for ML0+ having line 518 leading to Main Link RX inexternal display device 104. HSTX− pin 212 has a line 516 leading to theMain Link TX component. Pin 212 maps to pin 304 on display device 104 onthe ML0− line to Main Link RX. HSRX+ pin 214 has line 522 leading to anAUX CH TRX/enhanced serial interface HSRX component. Pin 214 connects toAUX+ pin 306 having AUX+ line 526 leading to an AUX CH TRX component.There is also a stub on line 526 leading to a Source Detector viaSRC_DETECT line. HSRX− pin 216 has AUX+/HSRX+ line 524 leading to AUX CHTRX/enhanced serial interface HSRX component. Pin 216 connects to AUX−pin 308 having AUX− line 528 leading to the AUX CH TRX. The last pin ofenhanced serial interface plug connector is GND pin 218 having an HPD_INline 530 leading to an HPD Detector. Off of line 530 are two stubs, onelabeled HPD_DETECT_CTRL that also leads to the HPD Detector. Pin 218connects with pin 310 corresponding to an HPD pin having line 532leading to an HPD Driver in display device 104. DP_PWR has a DP_PWR_OUTline 534 leading to DP_PWR Provider component.

The remaining pins are part of the serial interface backward compatibleportion. D+ pin 202 has a D+ line 536 leading to a serial interfaceDownstream (differential pair D+/D−) component. A corresponding D− pin204 has a line 538 leading to the same downstream component. Pins 202and 204 connect with D+pin 312 and D− pin 314 on external display device104. Each has a line, 540 and 542, respectively, that lead to a serialinterface Upstream D+/D− component. A Vbus pin 206 has a Vbus_in line544 leading to USB Vbus Consumer component. Pin 206 connects with Vbuspin 316 on display device 104 which has line 546 leading to a USB VbusProvider component. Finally, GND pin 208 has a line 548 leading toground as shown and is connected to pin 318 having a line 550 leading toground in display device 104.

FIG. 6 shows a second embodiment of packet-based interface source plugconnector 112. Only the portion of connector 112 that is different fromthe embodiment in FIG. 5 is shown. At the top is shown AUX+ pin 306having line 526 leading to the AUX CH TRX component with a stub forSRC_DETECT leading to a Source Detector. In this embodiment, HPD andAUX− are connected or multiplexed at 602 inside cable adaptor 106,specifically within connector 112. DP_PWR pin 410 does not share its pinwith any other input/output. The other three pins, 402, 404, and 406,are the same as 302, 304, and 306 in FIG. 3A. In this embodiment,multimedia device 102 does not support full enhanced serial interfaceoperation using HSTX/HSRX. This is the case even when phone 102 is notin packet-based interface source mode because there is an HPD signalstub 602 of the HSRX− line from multimedia device 102. Other features ofthis embodiment include multimedia device 102 getting powered fromexternal display device 104 when device 104 does not have a USBdownstream port since it receives power from DP_PWR pin 410 (part ofenhanced serial interface) as well as from Vbus pin 316 (part of serialinterface) as shown in FIGS. 3B and 5. Thus, total power to phone 102 is5V/500 mA (or 900 mA if external display is enhanced serial interface)from Vbus pin 316 in addition to 3.3V/500 mA from DP_PWR pin 410. Thisembodiment also supports simultaneous operations of packet-based displayinterface source isochronous transport of AV streams with High BandwidthDigital Content Protection (HDCP) and serial interface.

FIG. 7 is a flow diagram of a process of mapping signals and providingpower between an external display device and a multimedia device inaccordance with one embodiment. In other embodiments, other types ofhandheld devices having enhanced serial interface or a standard serialinterface and packet-based interface ports may be used. As noted above,the external display device may be a high-definition TV or other displaydevice, such as a computer monitor. A user having a multimedia devicewith content on it, such as digital videos or pictures, wants to displaythe content on a larger display, typically an HDTV. At the same time,the user may want to charge the phone without having to plug the phoneinto an electrical outlet. The user would prefer to use a single cablebetween the phone and the display device to simultaneously display ordownload the content and power the phone. However, the user may not beaware of the specific capabilities of the TV or the phone, such aswhether the phone is enhanced serial interface enabled or whether the TVhas a packet-based digital display interface connector.

At step 702, the multimedia device is powered on and, as part of itsnormal operation, it monitors GND pin 218 voltage and Vbus pin 206voltage. The action taken based on this monitoring is described afterstep 704. The passive cable adaptor of the present invention is used toconnect the multimedia device with the external display. The adaptorcable has one end that is an enhanced serial interface plug connectorwhich is inserted or engaged with an enhanced serial interface receivingconnector on the multimedia device. It will not engage with a serialinterface receiving connector. The other end of the cable connects tothe external display, such as an HDTV. The display may or may not beenhanced serial interface equipped and similarly, it may or may not bepacket-based interface-enabled. Once the multimedia device detects thata connection has been made by monitoring these pins, control goes tostep 704 where the external display supplies power to the phoneimmediately if the external display is already powered on or as soon asthe display is turned on. This power is supplied regardless of any otherdata transmissions that may be occurring between the phone and theexternal display, that is, no data needs to be transmitted between thetwo devices for power to be supplied from the external display.

Each pin (GND and Vbus) can be in one of two states: High or Low. Thus,there are four combinations of states or voltage levels. These are showin boxes 706 to 712. To be complete, the simplest case (and one that ispresumed to not be true because of actions taken at step 702), no deviceis connected to the multimedia device as shown in box 706. In this casethe multimedia device detects that the GND pin and the Vbus pin are bothlow, thus nothing is connected as indicated in box 714 and the processends. If the GND pin is H (“pulled up”) and the Vbus pin is H, as shownin box 708, it is determined by the multimedia device that the externaldisplay or device connected to via the passive adapter cable has apacket-based digital display interface and is a USB host as indicated bybox 716. The GND pin can only be pulled up if the device has apacket-based digital display interface. If the GND pin is H and the Vbuspin is L, it is determined that the external display only has apacket-based digital display interface and is not a USB host asindicated in box 718. Finally, if the GND pin is L and the Vbus pin is Has shown in box 712, the multimedia device knows that the externaldisplay is a USB host only as indicated in box 720 and the process iscomplete; no mapping takes place.

If the external device has a packet-based digital display interface(boxes 716 and 718), control goes to step 722 where a mapping isperformed between the packet-based interface signal and the enhancedserial interface connector signal. At step 722 the HSTX signals aremapped to ML0+/− signals. As can be derived from the figures above,HSTX+ maps to ML0+ and HSTX− maps to ML0−. The HSRX signals are mappedto AUX+/− signals. More specifically, HSRX+ maps to AUX+ and HSRX− mapsto AUX−. This is the mapping that takes place between the packet-basedinterface and enhanced serial interface and enables transport of AVstreams or other types of digital data (with HDCP) between the phone andTV. These steps are done simultaneously with supplying power performedat step 704. At this stage the multimedia device and TV are connectedand the TV is displaying data from the phone either via the packet-baseddigital display interface (and HSTX/HSRX) or via USB, and power is beingsupplied to the phone, as described in greater detail in FIG. 8.

FIG. 8 is a flow diagram of a process of supplying power from theexternal display to the multimedia device in accordance with oneembodiment. It shows in greater detail step 704 of FIG. 7. At step 802it is determined whether the external display device has serialinterface downstream capability. This can be done using techniques knownin the art. If the display does have downstream serial interfacecapability, then control goes to step 804 where power is supplied viathe Vbus pin on the serial interface backward-compatible connector andthrough the DP_PWR pin, part of the packet-based digital displayinterface receiving connector. In one embodiment, the amount of power is5V/500 mA. If the external display is an enhanced serial interface host,the power may be 5V/900 mA. If the external display does not have serialinterface downstream capability, control goes to step 806 where power issupplied to the multimedia device on through the DP_PWR pin.

In another embodiment, if the multimedia device or other sourcedetermines that the HPD_DETECT_CTRL is low, this is an indication thatthe external display device is not an enhanced serial interface host.This determination can be made by the HPD Detector component 552. IfHPD_DETECT_CTRL is not low, then the multimedia device has determinedthat the external display is an enhanced serial interface host.

Micro-Serial Interface Mapping

In another embodiment, packet-based digital display interface signalsare mapped to signals of a micro version of the serial interfaceconnector (hereafter “micro serial interface”). A micro serial interfaceconnector has a smaller connector and is suitable for mobile andhandheld devices for which a smaller connector would be more suitablethan the standard serial connector. FIG. 9 is an overview block diagramshowing a connection between a multimedia device and an external displaydevice in accordance with one embodiment. A multimedia device 920 isconnected to an external display device 922 via a micro serialinterface-to-packet-based interface cable adaptor 924. Multimedia device920 has a micro serial interface receiver port 926. External displaydevice 922 has a mated packet-based digital display interface receiverport 928. Cable 924 has a micro serial interface connector 932 at oneend that couples with receiver port 926 on multimedia device 920 and apacket-based display interface connector 930 (at the other end) thatcouples with receiver port 928 on external display 922. As with theembodiments described above, multimedia device 920 acts as apacket-based interface source device (i.e., it provides the multimediaor AV data stream, video, audio, graphics, etc.). It may also act as aserial interface device. External display device 922, such as an HDTVmay act as a packet-based digital interface sink device (i.e., itreceives the multimedia/AV stream and displays it) and as a serialinterface host device.

As described above, the packet-based digital interface protocol allowssideband communications that occur over auxiliary channels (AUX CH) tobe completed before beginning main link transmission of the multimediaor other type of data. This allows the main link and the auxiliarychannels to share the same differential pair (D+ and D−). As describedabove in FIG. 3B, a standard (i.e., not micro) serial interfaceconnector has four pins: D+, D− (480 Mbps, half-duplex bi-directional),Vbus (power, 5V), and GND. Micro serial interface connector 932 has fivepins. This type of connector is becoming increasingly common on handhelddevices, such as multimedia devices, video cameras, gaming devices, andother portable devices. Four of the pins in connector 932 are the sameas those in the standard serial interface and have the samecharacteristics, but with the addition of one pin that may be referredto as an “ID” pin for serial interface mobile support.

This ID pin is used for supporting serial interface mobile support onserial interface devices that can function either as a standard serialinterface device or as a limited serial interface device. In oneembodiment of the micro serial interface mapping technique describedherein, this ID pin is used for mapping hot plug detect (HPD). That is,HPD (part of the packet-based digital display interface) is mapped tothe ID pin of micro serial interface connector 932. The differentialpair, D+ and D−, of micro serial interface, is mapped to the main link(ML) of the packet-based display interface communication 930. Theauxiliary channel, AUX+ and AUX−, is mapped to the ID pin of microserial interface connector 932. The Vbus pin of micro serial interfaceis mapped to DP_PWR pin of the packet-based display interface. Mappingto the ID pin of micro serial interface involves use of an AUX_HPDcontroller described below.

In one embodiment, a micro serial interface cable adaptor, as shown inFIG. 10, having HPD detection logic, path selection logic, and adifferential switch, is used to connect a micro serial interfaceconnector on the multimedia device to a packet-based display interfaceconnector of an external display device, such as a TV. In thisembodiment, the multimedia device has packet-based display interfaceoutput capability and the external display device is also packet-baseddisplay interface enabled (i.e., it can receive this kind of input). Thecable adaptor having a micro serial interface plug connector at one end,has the ID pin of the micro serial interface connector tied to eitherVbus voltage of the packet-based display interface or leaves the IP pinfloating.

FIG. 10 is a block diagram showing in greater detail the componentsshown in FIG. 9 in accordance with one embodiment. On the left ismultimedia device (packet-based display interface source device) 920having connector 926, a standard micro serial interface connector havingfive pins, as described above. Connector 926 and components inmultimedia device 920 are described first. Vbus pin 934 has a line 936leading to a power circuit component (power consumer) in phone 920. GNDpin 938 leads to ground as shown in phone 920. A D+ pin 940 and D− pin942, comprising a differential pair, have lines 944 and 946,respectively, leading to a packet-based display interface main link (ML)TX lane 0/USB PHY component 948. ID pin 950 has a line 952 leading to acomponent 954 for AUX TX/RX and HPD detection and for serial interfacemobile ID detection.

Now, display device 922, on the right side of FIG. 10 is described. Itis, as noted, a packet-based display interface sink device. It has apacket-based interface connector 928 with various pins: HPD 954, AUX−956, AUX+ 958, ML0− 960, ML0+ 962, GND 964, and DP_PWR (packet-baseddisplay power) 966. These pins have lines which lead to components inexternal display device (sink device) 922 as shown in FIG. 10.

Cable adaptor 924 in the middle of FIG. 10 is now described. It is amicro serial interface to packet-based interface mapping cablecontaining various components. Connector 932 at one end of cable 924connects to the micro serial interface connector 926 of multimediadevice 920. Connector 932 has five pins that couple to the pins inconnector 926, namely, Vbus 934, GND 938, D+ 940, D− 942, and ID 950.The GND pins map to one another (pin 964 to pin 938). The DP_PWR pin 966from external display 922 maps to Vbus pin 934 via a DP_PWR to Vbusregulator component 968. The main link (ML) pins ML0+ 962 and ML0− 960of external display 922 connect to the differential pair, D+ 940 and D−942, on the multimedia device 920. More specifically, ML0+ maps to D+and ML0− maps to D−, via lines 970 and 972, respectively.

In one embodiment, the MicroUSB to packet-based display interfaceadaptor cable 924 has an AUX_HPD Controller 974 which has four signals.An AUX+ pin 958 and AUX− pin 956 (corresponding to the packet-basedinterface connector 930) are each differential IO, as shown incontroller 974. The HPD pin 954 leads to a single-ended input incontroller 974. On the micro serial interface connector 932 end, the IDpin 950 also leads to a single-ended IO in controller 974 which is alsotri-stateable.

Controller 974 performs various functions. In one embodiment it performsconversion between single-ended AUX CH signal (on the multimedia deviceside) and the differential AUX CH signal (on the external display deviceside). Controller 974 also forwards the HPD signal from display device922 to multimedia device 920. More specifically, when external display922 generates an HPD pulse while an auxiliary channel (AUX CH)transaction is in progress in one embodiment, AUX_HPD Controller 974forwards the HPD pulse as soon as the AUX reply transaction is completed(or if there is no reply, an AUX reply time-out occurs). In oneembodiment, Controller 974 leaves the output portion of ID pin 950tri-stated by default. With a resistor (e.g. 200 kΩ resistor), ID pin950 is weakly pulled-up to Vbus voltage within cable adaptor 924. TheAUX− pin 956 is weakly pulled-up to DP_PWR voltage with a resistor incable adaptor 924 (e.g., 100 kΩ) as shown in FIG. 10.

In one embodiment, multimedia device 920, or any device with a microserial interface connector and packet-based interface source capability,upon detecting Logic High level on ID pin 950 (a feature of the microserial interface standard), may discover the presence of packet-basedinterface-to-micro serial interface cable adaptor 924 by variousfeatures. One is by weakly pulling down the ID signal via a 200 kΩresistor and verifying that the ID signal remains at the Logic Highlevel. In this manner, multimedia device 920 can verify that the IDsignal is not floating, which indicates that adaptor cable 924 isconnected. In another embodiment, the ID signal may be pulled down via a20 kΩ resistor, followed by a verification that the ID signal is pulleddown to Logic Low level, thereby indicating that the ID signal is nottied to Vbus 934. This also indicates that cable adaptor 924 isconnected to multimedia device 920.

Multimedia device 920, having packet-based display interface-over-microserial interface capability, interoperates with regular packet-baseddisplay interface external displays. As with other packet-basedinterface source devices, multimedia device 920 can support EDID read,audio/video stream transport, and HDCP content protection of premium A/Vstream content. At 5.4 Gbps per lane (at High Bit Rate 2), packet-basedinterface-over-micro serial interface cable adaptor 924 is capable oftransporting FHD 60 Hz of uncompressed video stream.

In one embodiment, cable adaptor 924 is capable of performing an AUX CHhandshake for discovering whether a high-voltage external display deviceis present. This can be enabled as described below. A packet-basedinterface downstream device (such as display device 922), acting as aDP_PWR (power) producer, generates 3.3V by default on DP_PWR pin 966 viaconnectors 928/930 (mated packet-based interface connector), accordingto the packet-based interface standard described above. A downstreamdevice that is capable of generating a higher voltage, such as 12V+/−10%on DP_PWR pin 966, indicates that it has this capability by setting a12V_DP_PWR_CAP bit (Bit 0) of a DP_PWR_VOLTAGE_CAP field to 1(DP_PWR_VOLTAGE_CAP field corresponds to packet-based interfaceconfiguration data address 00010h). The upstream device, multimediadevice 920, may enable the 12V DP_PWR of the downstream device bysetting the 12V_DP_PWR_REQUEST bit (Bit 0) of aDP_POWER_VOLTAGE_SHIFT_REQUEST field to 1 (packet-based configurationdata address 00119h). Clearing the bit to 0 sets the DP_PWR voltage backto +3.3V+/−10%. The downstream display device that is capable ofgenerating 12V on DP_PWR pin 966 must be able to transition between 3.3Vand 12V without causing a voltage spike on the DP_PWR power rail. In oneembodiment, multimedia device 920 (upstream device) that requests aDP_PWR voltage shift avoids power-on reset and retains its states duringthe DP_PWR voltage shift.

Table 1 shows the packet-based interface configuration data fields thatare relevant to DP_PWR voltage shifts in accordance with one embodiment.Although the DP_PWR (power) voltage shift of external display device 922(downstream device) is of primary relevance to the packet-basedinterface signal mapping over micro serial interface cable adaptor 924,for completeness, Table 1 shows the fields for the power voltage shiftof multimedia device 920 as well.

TABLE 1 ADDRESS MAPPING FOR PACKET-BASED INTERFACE CONFIG DATA (CD) CDRead/Write over Address Definition AUX CH 00010h DP_PWR_VOLTAGE_CAP Readonly Bit 0 = 12V_DP_PWR_CAP 1 - Downstream device capable of producing12 V +/− 10% on the DP_PWR pin of its packet-based interface connector.0 - Downstream device not capable of producing 12 V +/− 10%; 3.3 V +/−10% only. Bits 7:1 = RESERVED 00119hDN_DEVICE_DP_PWR_VOLTAGE_SHIFT_REQUEST Write/Read Bit 0 =DN_DEVICE_12V_DP_PWR_REQUEST 1 - Requests for 12 V output on the DP_PWRpin of the packet- based interface connector of the downstream device.Don't care when DP_PWR_VOLTAGE_CAP field 12_DP_PWR_CAP bit is 0. 0 -Does not request for 12 V output on the DP_PWR pin of the DP connectorof the downstream device. DP_PWR is 3.3 V +/− 10%. Bits 7:1 = RESERVED0011Ah UP_DEVICE_DP_PWR_VOLTAGE_CAP_INDICATION Write/Read Bit 0 =UP_DEVICE_12V_DP_PWR_CAP 1 - Indicates to the downstream device thatthis upstream device is capable of producing 12 V +/− 10% on the DP_PWRpin of its packet-based interface connector. 0 - Indicates to thedownstream device that this upstream device is not capable of producing12 V +/− 10% on the DP_PWR pin of its packet-based interface connector;3.3 V +/− 10% only. Bits 7:1 = RESERVED 02004hDEVICE_SERVICE_IRQ_VECTOR_ESI1 Bit 0 = Bit 0 =RX_GTC_MSTR_REQ_STATUS_CHANGE Clearable Read The status ofRX_GTC_MSTR_REQ has changed. The Only. RX_GTC_MSTR_REQ is readable at CDAddress 00058h bit (Bit is cleared 0 when ‘1’ is Bit 1 =UN_DEVICE_12V_DP_PWR_REQUEST written via an Bits 7:2 = RESERVED. Readall 0 s AUX CH write transaction.) Bit 1 = Read only

Addresses 00010h and 00119h are relevant to the DP_PWR voltage shift ofthe (downstream) external display device while 0011Ah and 02004h arerelevant to the upstream device.

As noted above, the same differential pair (D+/−) signal traces 944 and946 in multimedia device 920 may be shared between the packet-baseddisplay interface main link (ML) 0+/− and serial interface D+/D−. In oneembodiment, this may be done by placing a passive bi-directional switch(multiplexer) on the PCB of multimedia device 920. This is shown in FIG.11. In this embodiment, it is important to ensure that placing theswitch in the multimedia device 920 will not cause significant signalquality degradation.

Referring to FIG. 11, micro serial interface connector pins 940 and 942,shown initially in FIG. 10, have differential pair lines, DIFF_POS 1102and DIFF_NEG 1104, (in the cable adaptor, they are D+ 940 and D− 942)leading from the pins to a bi-directional passive switch 1106. Switch1106 has a “1” portion and a “0” portion. DIFF_POS line 1102 leads tothe 1 portion and DIFF_NEG line 1104 leads to the 0 portion. Two linesfrom switch 1106, an ML0+ line 1108 and an ML0− line 1110 connect switch1106 to packet-based interface main link (ML) TX Lane0+/− component1112. Also shown are two 50 kΩ resistors and a Vtx_mL bias which isadjusted depending on whether packet-based digital display interfacecable adaptor 924 is detected or not. A cable adaptor detect signal 1114is transmitted to switch 1106. A cable adaptor can be detected asconnected to multimedia device 920 using the techniques described above.

A USB D+ line 1116 and a USB D− line 1118 connect switch 1106 with aserial interface D+/− component 1120. This component and component 1112are represented collectively as packet-based interface ML TXLane0/serial interface PHY component 948 in FIG. 10. Also shown in FIG.11 is an optional differential re-driver 1123 in cable adaptor 924.Cable adaptor 924 may also have AC-coupling caps 1124 and 1126. Thesemay also be placed in multimedia device 920.

In another embodiment, the packet-based ML TX PHY and the USB PHY sharethe same pads as shown in FIG. 12. Micro serial interface connector pins940 and 942 have a DIFF_POS line 1122 and DIFF_NEG line 1124 leading toa packet-based ML/USB Dual-Mode PHY component 1126. As in the firstembodiment, cable adaptor 924 may have a differential re-driver 1123. AVtx_mL bias adjusts depending on whether cable adaptor 924 is detected.

In one embodiment, the standard serial interface may be implementedusing USB2.0 and the enhanced serial interface may be implemented usingUSB3.0. High speed transmission (HSTX) may be implemented by SuperSpeedtransmission signals in the USB3.0 standard. Similarly, high speedtransmission (HSRX) may be implemented by SuperSpeed receiver signals inUSB3.0. Micro serial interface may be implemented by the MicroUSB2.0standard for mobile and handheld devices. The mobile support of theserial interface of the described embodiment may be implemented by theOn-The-Go (OTG) pin in the MircoUSB2.0 standard. Of course, otherstandards having a serial interface may also be used to implement thedescribed embodiments.

In addition, embodiments of the present invention further relate tointegrated circuits and chips (including system on a chip (SOC)) and/orchip sets or packages. By way of example, each of the devices describedherein may include an integrated circuit chip or SOC for use inimplementing the described embodiments and similar embodiments.Embodiments may also relate to computer storage products with acomputer-readable medium that has computer code thereon for performingvarious computer-implemented operations. The media and computer code maybe those specially designed and constructed for the purposes of thepresent invention, or they may be of the kind well known and availableto those having skill in the computer software arts. Examples oftangible computer-readable media include, but are not limited to:magnetic media such as hard disks, floppy disks, and magnetic tape;optical media such as CD-ROMs and holographic devices; magneto-opticalmedia such as floptical disks; and hardware devices that are speciallyconfigured to store and execute program code, such asapplication-specific integrated circuits (ASICs), programmable logicdevices (PLDs) and ROM and RAM devices. Examples of computer codeinclude machine code, such as produced by a compiler, and filescontaining higher level code that are executed by a computer using aninterpreter. Computer readable media may also be computer codetransmitted by a computer data signal embodied in a carrier wave andrepresenting a sequence of instructions that are executable by aprocessor. In addition to chips, chip systems, and chip sets, theinvention can be embodied as firmware written to said chips and suitablefor performing the processes just described.

The foregoing description, for purposes of explanation, used specificnomenclature to provide a thorough understanding of the invention.However, it will be apparent to one skilled in the art that the specificdetails are not required in order to practice the invention. Thus, theforegoing descriptions of specific embodiments of the present inventionare presented for purposes of illustration and description. They are notintended to be exhaustive or to limit the invention to the precise formsdisclosed. It will be apparent to one of ordinary skill in the art thatmany modifications and variations are possible in view of the aboveteachings.

The embodiments were chosen and described in order to best explain theprinciples of the invention and its practical applications, to therebyenable others skilled in the art to best utilize the invention andvarious embodiments with various modifications as are suited to theparticular use contemplated. It is intended that the scope of theinvention be defined by the following claims and their equivalents.

1. A method of mapping signals between a multimedia data source deviceand an external display device, the method comprising: mappinghigh-speed transmission signals (“HSTX”) to main link signals of apacket-based interface; mapping high-speed receiving signals (“HSRX”) toauxiliary channel signals of the packet-based interface, wherein saidmappings enable transport of a multimedia data stream; and enablingpower supply from the external display device to the source device usinga serial interface connection while simultaneously transporting themultimedia data stream.
 2. A method as recited in claim 1 furthercomprising: mapping a ground signal of the data source device to apacket-based display interface hot plug detect signal.
 3. A method asrecited in claim 1 wherein mapping high-speed transmission signals tomain link signals further comprises: mapping a HSTX positive signal to amain link positive signal; and mapping a HSTX negative signal to a mainlink negative signal.
 4. A method as recited in claim 1 wherein mappinghigh-speed receiving signals to auxiliary channel signals furthercomprising: mapping high-speed receiving positive signal to an auxiliarychannel positive signal and mapping high-speed receiving negative signalto an auxiliary channel negative signal.
 5. A method as recited in claim1 further comprising: mapping a high-speed receiving negative signal toa packet-based interface negative auxiliary pin signal.
 6. A method asrecited in claim 5 further comprising: multiplexing the packet-basedinterface negative auxiliary signal and a hot plug detect signal.
 7. Amethod as recited in claim 1 wherein supplying power further comprises:determining whether the external display device has serial interfacedownstream capability.
 8. A method as recited in claim 7 furthercomprising supplying power through a packet-based interface power pin ifthe external display device does not have serial interface downstreamcapability.
 9. A method as recited in claim 7 further comprisingsupplying power through a Vbus pin and a packet-based interface powerpin, if the external display device does have serial interfacedownstream capability.
 10. A method as recited in claim 1 wherein thesource is a multimedia device and the external display device is atelevision.
 11. A cable adaptor for connecting a data source device witha display device, the cable adaptor comprising: a packet-based interfaceconnector at a first end having a positive main link pin, a negativemain link pin, a positive auxiliary channel pin, and a negativeauxiliary channel pin; a serial interface connector at the first end;and an enhanced serial interface connector at a second end having highspeed transmission (“HSTX”) pins, high speed receiver (“HSRX”) pins, anda ground pin, wherein multimedia content is transmitted over the cableadaptor and electrical power is supplied over the cable adaptorsimultaneously.
 12. A cable adaptor as recited in claim 11 wherein thepacket-based interface connector further comprises: a pin for hot plugdetect (HPD) signals.
 13. A cable adaptor as recited in claim 11 whereinthe positive main link pin connects to a positive HSTX pin in the datasource device and the negative main link pin connects to a negative HSTXpin in the data source device.
 14. A cable adaptor as recited in claim11 wherein the positive auxiliary channel pin connects to a positiveHSRX pin in the data source device and the negative auxiliary channelpin connects to a negative HSRX pin in the data source device.
 15. Acable adaptor as recited in claim 12 wherein the pin for HPD connects toa ground pin.
 16. A cable adaptor as recited in claim 12 wherein the pinfor HPD connects to a negative HSRX pin.
 17. A cable adaptor as recitedin claim 12 wherein the negative auxiliary channel pin is multiplexedwith the pin for HPD.
 18. A method of transmitting data and supplyingpower between a multimedia data source and an external display device,the method comprising: supplying power from the display device to thedata source; monitoring a ground voltage level and a Vbus voltage level;and performing a mapping of packet-based signals and USB signals.
 19. Amethod as recited in claim 18 wherein performing a mapping furthercomprises: mapping an HSTX positive pin with a positive main link pin;and mapping an HSTX negative pin with a negative main link pin.
 20. Amethod as recited in claim 18 wherein performing a mapping furthercomprises: mapping an HSRX positive pin with a positive auxiliary pin;and mapping an HSRX negative pin with a negative auxiliary pin.
 21. Amethod as recited in claim 18 wherein supplying power further comprises:if the external display device has serial interface downstreamcapability, supplying power using a Vbus pin and a packet-basedinterface power pin.
 22. A method as recited in claim 18 whereinsupplying power further comprises: if the external display device doesnot have serial interface downstream capability, supplying power using apacket-based interface power pin.
 23. A method as recited in claim 18wherein power is supplied while the multimedia data is being transmittedfrom the source to the display device.